Silicon Metal 553 / 441 / 3303

Silicon Metal is supplied across the full ladder of metallurgical and chemical grades: 553, 441, 3303, 3503, 3505, 4403, 4406, 2202 and 1101, with 553 and 3303 the most widely traded. The designation encodes maximum impurity levels. Grade 553 permits up to 0.5% Fe, 0.5% Al and 0.3% Ca; 3303 tightens iron and aluminium to 0.3% and calcium to 0.03%. In aluminium casting, silicon is the primary alloying addition: it improves fluidity, reduces shrinkage and raises hardness, and virtually every cast automotive component contains it. Silicon metal also feeds the silicone chemicals and semiconductor supply chains.